Alteration of Swallowing and Ventilation Coordination in Respiratory Diseases in Small Mammals.

In human and animal, swallowing and ventilation are coordinated to avoid laryngeal penetration or tracheal aspiration, and respiration is interrupted during swallowing and resumes in the expiratory phase. Some respiratory diseases may alter this coordination due to impaired lung function. The aim of this study was to evaluate swallowing-ventilation coordination in unrestrained rats with pulmonary emphysema or with pulmonary fibrosis. Two protocols were performed in 38 male Sprague-Dawley rats (2-3 months, 250-300 g): pulmonary emphysema and pulmonary fibrosis. Ventilation during swallowing and swallowing-ventilation coordination were recorded using a whole-body plethysmography and video recordings. The rats were free to take water after 24 h without drinking. Compared to control groups, swallowing frequency was significantly higher in rats with pulmonary emphysema and there was a decrease of swallows during expiration in rats with pulmonary emphysema and in rats with pulmonary fibrosis. In this study, we show that respiratory diseases are associated with changes in swallowing-ventilation coordination and hypothesize that they increase the risk of aspiration.

Swallowing Disorders in Severe Brain Injury in the Arousal Phase.

The objective of this study was to determine the clinical characteristics of swallowing disorders in severe brain injury in the arousal phase after coma. Between December 1, 2013 and June 30, 2014, eleven patients with severe acquired brain injury who were admitted to rehabilitation center (Male 81.8 %; 40.7 ± 14.6 years) were included in the study. Evaluation of swallowing included a functional examination, clinical functional swallowing test, and naso-endoscopic swallowing test. All patients had swallowing disorders at admission. The first functional swallowing test showed oral (77.8 %) and pharyngeal (66.7 %) food bolus transport disorders; and alterations in airway protection mechanisms (80 %). Swallowing test under endoscopic control showed a disorder in swallowing coordination in 55.6 % of patients tested. Seven (63.6 %) patients resumed oral feeding within an average of 6 weeks after admission to rehabilitation center and 14 weeks after acquired brain injury. Six (85.7 %) of these seven patients continued to require modified solid and liquid textures. Swallowing disorders are a major concern in severe brain injury in the arousal phase. Early bedside assessment of swallowing is essential for detection of swallowing disorders to propose appropriate medical rehabilitation care to these patients in a state of altered consciousness.

Effect of transcranial magnetic stimulation on rectal sensitivity in irritable bowel syndrome: a randomized, placebo-controlled pilot study.

AIM: Repetitive transcranial magnetic stimulation (rTMS) applied to the motor cortex can induce analgesic effects in patients with chronic pain syndromes through its effect on central pain-modulatory systems. Our aim was to evaluate the effect of rTMS on rectal sensitivity in irritable bowel syndrome (IBS) patients. METHOD: In this randomized, sham-controlled, proof-of concept trial, 21 IBS patients (11 women and 10 men; mean age 44.0 ± 12.6 years) were randomized, using a double-blind crossover protocol, to active or sham rTMS for 5 days of treatment. The primary outcome was the increase in the pressure pain threshold after rTMS. Secondary outcomes were the changes in maximum tolerated rectal volume, rectal compliance and average pain intensity between baseline and the end of the treatments. RESULTS: There were no statistically significant differences between active and sham rTMS in terms of an increase in the pressure pain threshold, maximum tolerated volume and rectal compliance at the end of the treatments compared with baseline. However, in the subgroup of patients with the most marked rectal hypersensitivity, the volume threshold was significantly improved by active, but not by sham, rTMS (P = 0.03). Patients experienced a significant improvement in pain regardless of the type of stimulation. CONCLUSION: This pilot study failed to demonstrate any benefit of rTMS on our primary end-point. However, the effect of rTMS on rectal tolerated volume in the most hypersensitive patients was encouraging enough to plan more powered studies.

Can multichannel intraluminal pH-impedance monitoring be limited to 3 hours? Comparison between ambulatory 24-hour and post-prandial 3-hour recording.

Esophageal multichannel intraluminal pH-impedance recording (MII) is now a valid technique for determining the acidic, liquid, gas or mixed nature of gastroesophageal reflux episodes. However, some recordings may stop prematurely due to technical reasons or poor patient tolerance of the probe. Therefore, we questioned whether analysis of post-prandial 3-hour recording could predict the results obtained in ambulatory 24-hour recording. Fifty patients with symptoms of gastroesophageal reflux disease were investigated. For each patient, post-prandial 3-hour MII was recorded after a test meal, then followed by ambulatory 21-hour MII. Correlation between the total number of liquid reflux events in the 3-hour and 24-hour recordings was elevated (R=0.71; P<0.001), with better correlation for acid (R=0.80; P<0.001) and weak acid reflux (R=0.56; P<0.001) than non-acid reflux (R=0.44; P<0.01). Sensitivity and specificity of 3-hour recording in detecting elevated liquid reflux over 24 hours (id>75reflux/24 h) were 49% and 100%, respectively, for 8 or less liquid/mixed reflux events per 3 hours, and 78% and 88%, respectively for 15 or more liquid/mixed reflux events per 3 hours. The sensitivity and specificity of symptom association probability (SAP) calculated over 3 hours were 56% and 91%, respectively. In conclusion, we identified relevant indicators on the 3-hour post-prandial recording likely to give accurate prediction of absence or presence of gastroesophageal reflux disease from 24-hour MII recording.

Evoked pressure curves from the external anal sphincter following transcranial magnetic stimulation in healthy volunteers and patients with faecal incontinence.

AIM: The hypothesis was tested that evoked pressure curves (EPCs) after transcranial magnetic stimulation (TMS) would provide additional neuropathophysiological information on the descending pathways to the external anal sphincter (EAS) in patients with faecal incontinence (FI). METHOD: Twenty-five healthy subjects and 69 patients with FI were investigated. TMS was applied to the vertex, and EPCs were recorded with a probe placed through the EAS. TMS was performed with the EAS at rest and during contraction (facilitated responses). At least three responses were recorded for each modality. Clinical data and anorectal manometric, electrophysiological perineal and transanal ultrasound recordings were compared with respect to the EPC results. RESULTS: There was no statistically significant difference between the EPCs of healthy subjects and FI patients. Twenty-three per cent of the FI patients had abnormal EPC latencies, with significantly lower voluntary contraction amplitudes (P = 0.03) and significantly higher rectal sensation (P = 0.04) than the other group. We found no significant difference between FI patients with and without abnormal EPC latencies in terms of clinical characteristics and electrophysiological and endoanal ultrasound parameters. There was no difference in the identified causes of the FI between the two groups. CONCLUSION: As abnormal EPC latencies were found in 23% of FI patients with no known central neurological disease, abnormal EPC latencies might reveal undetected lesions of descending pathways in patients with FI.

Oropharyngeal dysphagia in amyotrophic lateral sclerosis alters quality of life.

Dysphagia is one of the most important complications encountered in amyotrophic lateral sclerosis (ALS). Our aim was to determine whether oropharyngeal dysphagia impacted the quality of life (QoL) of patients with ALS. Thirty consecutive patients were recruited (31-82 years, 18 men). Swallowing function was evaluated using a standardised videofluoroscopic barium swallow. All the patients completed a specific questionnaire on quality of life in dysphagia (SWAL-QoL) immediately after the videofluoroscopy. The results of dysphagia outcome severity scale separated 14 patients with oropharyngeal dysphagia and 16 with normal swallowing function. There was no difference in the average age, weight and body mass index of the two groups (dysphagic patients: 68 ± 11 kg versus non-dysphagic patients: 69 ± 14 kg). Most of the dysphagic patients had a bulbar affection based on their Norris scores which determine the importance of cranial nerves illness (20 ± 8), significantly lower than those of the non-dysphagic patients (35 ± 5) (P < 0·0001). There was no difference in the neurological peripheral symptoms evaluated by Amyotrophic Lateral Sclerosis Functional Rating Scale scores (dysphagic patients: 26 ± 7 versus non-dysphagic patients: 27 ± 8) (ns). The swallowing quality of life questionnaire revealed that the dysphagic patients had significant burden (P < 0·001). They were affected by the necessity to applied a food selection (P < 0·01), by the increase in eating duration (P < 0·05) and described a decrease in eating desire (P < 0·05). They complained of fear regarding the risk of dysphagia (P < 0·05). They also described difficulties with oral communication (P < 0·001). All of those complained about dysphagia which impacted directly mental health (P < 0·05) and social life (P < 0·05). In conclusion, oropharyngeal dysphagia is a common symptom accompanying ALS, which alters the patient's QoL, especially social health.

Prevalence and evaluation of oropharyngeal dysphagia in patients with severe acute respiratory syndrome coronavirus 2 infection in the intensive care unit.

OBJECTIVE: The main objective was to assess the prevalence of dysphagia in the intensive care unit in patients with coronavirus disease 2019.Methods. A cohort, observational, retrospective study was conducted of patients admitted to the intensive care unit for severe acute respiratory syndrome coronavirus 2 pneumonia at the University Hospital of Rouen in France. RESULTS: Over 4 months, 58 patients were intubated and ventilated, 43 of whom were evaluated. Screening revealed post-extubation dysphagia in 62.7 per cent of patients. In univariate analysis, a significant association was found between the presence of dysphagia and: the severity of the initial pathology, the duration of intubation, the duration of curare use, the degree of muscle weakness and the severity indicated on the initial scan. At the end of intensive care unit treatment, 22 per cent of the dysphagic patients had a normal diet, 56 per cent had an adapted diet and 22 per cent still received exclusive tube feeding. CONCLUSION: Post-extubation dysphagia is frequent and needs to be investigated.

Poststroke dysphagia rehabilitation by repetitive transcranial magnetic stimulation: a noncontrolled pilot study.

Poststroke dysphagia is frequent and significantly increases patient mortality. In two thirds of cases there is a spontaneous improvement in a few weeks, but in the other third, oropharyngeal dysphagia persists. Repetitive transcranial magnetic stimulation (rTMS) is known to excite or inhibit cortical neurons, depending on stimulation frequency. The aim of this noncontrolled pilot study was to assess the feasibility and the effects of 1-Hz rTMS, known to have an inhibitory effect, on poststroke dysphagia. Seven patients (3 females, age = 65 +/- 10 years), with poststroke dysphagia due to hemispheric or subhemispheric stroke more than 6 months earlier (56 +/- 50 months) diagnosed by videofluoroscopy, participated in the study. rTMS at 1 Hz was applied for 20 min per day every day for 5 days to the healthy hemisphere to decrease transcallosal inhibition. The evaluation was performed using the dysphagia handicap index and videofluoroscopy. The dysphagia handicap index demonstrated that the patients had mild oropharyngeal dysphagia. Initially, the score was 43 +/- 9 of a possible 120 which decreased to 30 +/- 7 (p < 0.05) after rTMS. After rTMS, there was an improvement of swallowing coordination, with a decrease in swallow reaction time for liquids (p = 0.0506) and paste (p < 0.01), although oral transit time, pharyngeal transit time, and laryngeal closure duration were not modified. Aspiration score significantly decreased for liquids (p < 0.05) and residue score decreased for paste (p < 0.05). This pilot study demonstrated that rTMS is feasible in poststroke dysphagia and improves swallowing coordination. Our results now need to be confirmed by a randomized controlled study with a larger patient population.

Validation in French of the SWAL-QOL scale in patients with oropharyngeal dysphagia.

A quality-of-life (QOL) questionnaire specifically designed for patients with oropharyngeal dysphagia (SWAL-QOL) has been elaborated and validated by Colleen McHorney. The aim of the present study was to validate the French translation of the SWAL-QOL in 73 patients with either post-stroke or post-surgical oropharyngeal dysphagia. The French version was considered understandable and acceptable by the study patients, who completed the questionnaire in approximately 20 minutes. However, 32 patients needed help in filling out the questionnaire-mostly in reading the questions and writing the answers. Completion was excellent, although seven patients missed one item. Analysis of convergent validity of the French version showed good correlation between items and the corresponding scale. Validity convergence was excellent for all the different items, with a correlation between each item and its own scale that was always greater than 0.40. Internal coherence was also excellent, with Cronbach's alpha coefficient greater than 0.7. Patients with oropharyngeal dysphagia have a poor QOL, as reflected by their very low scores. The lowest scores were related to the impact of swallowing disorders on the QOL (47+/-30) and on mental health (51+/-31). This study also demonstrated the linguistic and psychometric validity of the French version of the SWAL-QOL questionnaire.

Mylohyoid motor-evoked potentials relate to swallowing function after chronic stroke dysphagia.

This work aimed to study mylohyoid motor-evoked potentials (MHMEPs) and examined if it is related to chronic stroke dysphagia. Conduction time (CT) and amplitudes of the right and left MHMEPs in response to focal cortical magnetic stimulations over affected and unaffected hemispheres were recorded in 16 stroke patients with aspiration (n = 9) or residue (n = 7) and compared with eight control patients. In control group, MHMEPs were present on ipsilateral and contralateral sides after stimulation of both hemispheres and permitted to determine a dominant hemisphere. In stroke patients, after stimulation of the affected hemisphere, ipsilateral MEPs had a longer CT and lower amplitudes in patients with aspiration compared with patients with residue or control patients (P < 0.05). Contralateral CT was not different between the three groups, but amplitudes were lower in patients with residue and aspiration than in control patients (P < 0.01). In the unaffected hemisphere, MHMEPs were present, and not different between the three groups for the ipsilateral side and amplitudes were decreased in contralateral side in patients with residue. In conclusion, MHMEP alterations of the affected hemisphere related to chronic stroke dysphagia severity and were closed to normal in the unaffected hemisphere.

Effect of liquid properties on swallowing and ventilation coordination in rats.

BACKGROUND: One aspect of rehabilitation in swallowing disorders is to change liquid properties. The objective of our study was to test how liquid properties could improve oropharyngeal dysphagia and swallowing and ventilation coordination in an animal model. METHODS: Forty-two healthy male rats were distributed in six groups, including a control group. Rats were deprived of water for 24 h and then each group was administered liquid with different properties: tap water, sugar water, sparkling water, salt water, cold water, and acidic water. Rats were studied without and with oropharyngeal dysphagia achieved by unilateral section of the hypoglossal nerve. Swallowing and ventilation were analyzed by barometric plethysmograph. KEY RESULTS: In healthy rats, swallowing occurred during expiratory time for all liquid properties. Most deglutitions were during expiratory time for all liquid properties (88±12%) and were not modified. There was an increase in VT/TI during swallowing with sparkling water and cold water (P<.05). In the operated groups, rats had significantly fewer swallows with tap water (P<.05) and significantly more swallows with sparkling water (P<.001), sugar water (P<.001) and cold water (P<.001) during expiratory time. The mean inspiratory volume (VT/TI) increased with sparkling water (P<.05). CONCLUSION AND INFERENCES: Sparkling water seemed to improve swallowing and ventilation coordination in an animal model, to be confirmed in a study including patients with oropharyngeal dysphagia.

Normal values and day-to-day variability of 24-h ambulatory oesophageal impedance-pH monitoring in a Belgian-French cohort of healthy subjects.

BACKGROUND: Impedance-pH monitoring is the most sensitive method for detection and characterization of gastro-oesophageal reflux episodes. Normal values from European subjects are lacking. AIM: To build a database of gastro-oesophageal reflux patterns from French and Belgian healthy subjects. METHODS: Seventy-two healthy subjects (35 men, mean age 35 years, 18-72) underwent 24-h ambulatory impedance-pH studies. Gastro-oesophageal reflux episodes were detected using impedance and characterized by pH as acid, weakly acidic, or weakly alkaline. Analysis was performed visually and effects of age, gender and intra-individual reproducibility were evaluated. RESULTS: The total number of gastro-oesophageal reflux episodes was 44 (25,58,75) of which 59% were acid, 28% were weakly acidic and 10% weakly alkaline. Half of gastro-oesophageal reflux episodes were mixed (liquid/gas) and 22% reached 15 cm above the lower oesophageal sphincter. The bolus clearance time was 11 s while acid was chemically cleared in 34 s. Male gender was associated with increased number and proximal extent of total and acid gastro-oesophageal reflux. Repeated studies in 27 subjects showed good reproducibility for number, acidity and air-liquid composition of reflux (Kendall's W-values = 0.72-0.85). CONCLUSIONS: This study demonstrates good reproducibility of 24-h ambulatory impedance-pH studies and provides values of reflux patterns in healthy subjects for comparisons with European gastro-oesophageal reflux disease patients.

Impediment in upper airway stabilizing forces assessed by phrenic nerve stimulation in sleep apnea patients.

BACKGROUND: The forces developed during inspiration play a key role in determining upper airway stability and the occurrence of nocturnal breathing disorders. Phrenic nerve stimulation applied during wakefulness is a unique tool to assess Upper airway dynamic properties and to measure the overall mechanical effects of the inspiratory process on UA stability. OBJECTIVES: To compare the flow/pressure responses to inspiratory and expiratory twitches between sleep apnea subjects and normal subjects. METHODS: Inspiratory and expiratory twitches using magnetic nerve stimulation completed in eleven untreated sleep apnea subjects and ten normal subjects. RESULTS: In both groups, higher flow and pressure were reached during inspiratory twitches. The two groups showed no differences in expiratory twitch parameters. During inspiration, the pressure at which flow-limitation occurred was more negative in normals than in apneic subjects, but not reaching significance (p = 0.07). The relationship between pharyngeal pressure and flow adequately fitted with a polynomial regression model providing a measurement of upper airway critical pressure during twitch. This pressure significantly decreased in normals from expiratory to inspiratory twitches (-11.1 +/- 1.6 and -15.7 +/- 1.0 cm H2O respectively, 95% CI 1.6-7.6, p < 0.01), with no significant difference between the two measurements in apneic subjects. The inspiratory/expiratory difference in critical pressure was significantly correlated with the frequency of nocturnal breathing disorders. CONCLUSION: Inspiratory-related upper airway dilating forces are impeded in sleep apnea patients.

What are the perspectives for ventilated tetraplegics? A French retrospective study of 108 patients with cervical spinal cord injury.

OBJECTIVE: Tetraplegic patients are often difficult to manage in intensive care units (ICU). The aim of our study was to calculate the incidence of patients in ICU with cervical spinal cord injury with special focus on tetraplegic patients on ventilation support and their future perspectives. MATERIALS AND METHODS: This retrospective study included patients with cervical spinal cord injury in Upper Normandy, between 2002 and 2012. Data analyzed included age, sex, past medical history, date of onset of quadriplegia, level of neurological involvement, AIS grade, and ventilatory status. RESULTS: One hundred and eight patients were included (49.0 ± 21.1 years). The most common etiology was fall (50 patients [46.3%]). Incidence was calculated at 12.7 per one million inhabitants. Tracheotomy was performed in 40.7% of patients. Long-term mechanical ventilation was required for 6.5%. At the end of the study, 9 patients (9.6%) were permanently hospitalized, 61 patients (64.9%) had returned home but none of the four ventilated patients had been discharged. CONCLUSION: The conclusion of this work is that the future of highly tetraplegic patients is compromised, especially for those who remain reliant on mechanical ventilation.

Impact of deep brain stimulation on pharyngo-esophageal motility: a randomized cross-over study.

BACKGROUND: Bilateral subthalamic nucleus (STN) stimulation is used to alleviate Parkinson's disease (PD) motor symptoms. Recently, it has been shown that this therapeutic also increased gut cholinergic contractions. We therefore investigated the effect of STN stimulation on esophageal motility in an interventional randomized study. METHODS: Sixteen humans PD patients (4 women, 12 men; age: 62.4 ± 9.3-years old) who underwent STN stimulation for at least 6 months were randomly evaluated with either stimulator turned OFF then ON, or inversely. Esophageal high resolution manometry was performed at the end of each ON and OFF period, with a 5 min resting period followed by ten swallows of 5 mL. KEY RESULTS: During the ON, an increase in the distal contractility index was found (OFF: 1750 ± 629 vs ON: 2171 ± 755 mmHg/cm/s; p = 0.03), with no difference in the distal front velocity. A decrease in the integrative relaxation pressure of the lower esophageal sphincter (LES) was noted (OFF: 11.1 ± 1.8 mmHg vs ON: 7.2 ± 1.8 mmHg; p < 0.05) in ON. The LES resting pressure remained unchanged during the two periods. This resulted in a decrease in the intrabolus pressure (p = 0.03). No difference was observed for the upper esophageal sphincter, nor the pharyngeal contraction amplitude and velocity. CONCLUSIONS & INFERENCES: In conclusion, STN stimulation in PD patients increased esophageal body contractions and enhanced the LES opening. This suggests that the nigrostriatal-striatonigral loop is involved in the control of esophageal motility.

Prevalence of daytime hypercapnia or hypoxia in patients with OSAS and normal lung function.

The purpose of this study was to determine factors increasing daytime PaCO2 or PaO2 in obstructive sleep apnoea syndrome patients (OSAS) with normal pulmonary function tests. Anthropometric, pulmonary function tests, arterial blood gases and sleep polygraphic data were analysed retrospectively in 218 OSAS patients (apnoea-hypopnoea index > 15 h(-1); 18 females, 55 +/- 11 years): 125 patients had abnormal pulmonary function tests, i.e. one or more flow or volume under 80% or above 120% of predictive value (group I) and 93 had normal pulmonary function tests (group II). Hypercapnia was defined as PaCO2 > or = 6.0 kPa and hypoxia as PaO2 < 9.3 kPa. Patients with abnormal pulmonary function tests were more hypoxic and hypercapnic, more obese, and had a higher apnoea-hypopnoea index (P<0.05). Seventeen patients of group I and four of group II were hypercapnic (13.6% and 4.3%, respectively). Thirty-one patients in group I (24.8%) had a PaO2 < 9.3 kPa and six (6.5%) in group II. Stepwise multiple regression analysis showed that in group II, only two factors were correlated with PaCO2: mean apnoea duration and FRC (respectively: c=0.228, P<0.001; c=0.006, P=0.108); and only two with PaO2: mean apnoea duration: (c=-0.218, P=0.029) and BMI (c=-3.72, P<0.0001). Daytime hypercapnia is present in 4.3% and daytime hypoxia in 6.5% of patients with occlusive sleep apnoea syndrome and normal pulmonary function tests. These alterations in blood gases in OSAS with normal pulmonary function tests should be considered as OSAS severity criteria.

Usefulness of phrenic nerve stimulation to measure upper airway collapsibility in normal awake subjects.

Upper airway (UA) collapsibility can be characterized during sleep by looking at the changes in inspiratory flow limitation (IFL) with changing nasal pressure. IFL can be induced during wakefulness using phrenic nerve stimulation (PNS) applied during exclusive nasal breathing. The aim of the study was to evaluate the possibility of measuring UA critical pressure (Pcrit) in normal awaked subjects using electrical PNS (EPNS) or bilateral anterior magnetic phrenic stimulation (BAMPS). Instantaneous flow, esophageal (Peso) and mask pressures (Pmask), and genioglossal (GG) end-expiratory EMG activity were recorded in 13 normal subjects (4F, 9M) with randomly changing Pmask (0 to -20 cmH2O). For each trial, we examined the relationship between maximal inspiratory flow (Vtmax) of IFL twitches and the corresponding Pmask. Pcrit could be determined in 12 subjects (mean -33.5 +/- 16.3 cmH2O). No difference in Pcrit values was found between the EPNS and BAMPS methods but the strength of the Vtmax/Pmask relationship was higher with BAMPS. GG end-expiratory EMG activity increased with decreasing Pmask but no significant relationship was found between the slope of the GG end-expiratory EMG activity/Pmask relationship and Pcrit. We conclude that: (1) Pcrit can be measured during wakefulness in normal using PNS: (2) Pcrit measurements may be easier and more reliable with BAMPS than EPNS: and (3) Pcrit does not seem to be influenced by the pressure-related changes in GG end-expiratory EMG.

Heart rate variation after breath hold diving with different underwater swimming velocities.

BACKGROUND: The aim of this study was to demonstrate the kinetics of heart rate and blood lactate level obtained after repeated short breath holds with muscular effort in a swimming pool. EXPERIMENTAL DESIGN: each subject had to perform a series of breath hold diving at rest and three series for different underwater swimming velocities. A series corresponded to six dives of a 30 sec duration separated by a recovery period of 30 sec. Heart rates and blood lactate levels were measured at rest and at the end of each series of breath holds. PARTICIPANTS: the population was composed of 10 male subjects divided into one trained group (5 experts) and one group of 5 beginners. RESULTS: Results indicated a higher bradycardia for the expert group at static breath hold (54.25 vs 65.5 beats x min-1). At the end of a series of breath holds, tachycardia was higher for beginners at different underwater swimming velocities. These values were less significant than the heart rate measured in laboratory despite trials that were abandoned due to high blood lactate levels above 3.5 mmol x l-1. In order to avoid the breath hold breaking point, the maximum heart rate had to correspond to the heart rate of the ventilatory threshold measured in the laboratory, minus the variations of bradycardia measured at rest. CONCLUSIONS: For the training coach, bradycardia was determined by water immersion during a static breath hold. This permitted an evaluation of the level of diver training. A maximal heart rate was attempted to avoid the breath hold breaking point. The results of this study may be useful in creating an effective diver training program.